Children in the child welfare system are at high risk for serious disruptive behavior problems, including conduct disorder. Therefore, the prevention or reduction of early behavior problems is critical to improving long term outcomes for the vulnerable population of children in the child welfare system. The purpose of our project is to: (a) determine if Pathways Triple P results in better behavioral and safety outcomes than treatment as usual (TAU) for African American and European American children in the child welfare system and (b) evaluate how the cost-effectiveness of Pathways Triple P compares to TAU. Specifically, the aims of this study are to: (1) conduct a longitudinal, randomized control trial with 140 parents in the metro-St. Louis child welfare system (whose children are in their care at the time of study entry) to test the effectiveness of Pathways Triple P at improving child disruptive behavior among children between the ages of 5 and 10 compared to TAU. (2) Test the effectiveness of Pathways Triple P at preventing maltreatment recidivism; and (3) Measure and evaluate the costs and benefits associated with Pathways Triple P and TAU. A mixed method design will be used to test the hypotheses and answer the research questions associated with each aim. The study design is longitudinal with two treatment conditions and four data collection points: pre-test, post-test, follow-up 1 (F1, 6 months after post-test) and follow-up 2 (F2, 12 months after F1). Multiple assessment methods will be used: (1) computerized standardized instruments administered to parents, (2) semi-structured interviews with parents, (3) paper-based standardized instrument administered to teachers and (4) linking study data with a multi-sector state administrative dataset. Findings from this study will determine if Pathways Triple P results in optimal child behavior outcomes and prevents maltreatment recidivism among the vulnerable child welfare population, will identify for whom and under what conditions Pathways Triple P is most beneficial to parents to the target population, and will help target scarce federal dollars to serve children in the child welfare system. PUBLIC HEALTH RELEVANCE: The child welfare system serves large numbers of maltreated children with or who are at risk of developing serious disruptive behavior problems that can carry lifelong consequences, and put society at risk of violent crime. Efficacious parent-mediated interventions are available for preventing and treating these problems; however, to date, have only been implemented and tested sporadically within child welfare settings. Findings from this study will inform best practice and policy related to providing mental health interventions within child welfare settings.